Double Band-Pass Birdcage RF Coil for Dual Elements NMR Imaging at 4.7T MRI system

We proposed a novel dual resonance RF coil based on a band pass birdcage configuration for the detection of NMR signals of dual elements with different resonance frequencies. The proposed method is featured by the generation of two well separated leg current-based resonance frequency spectrums by splitting each leg of a conventional birdcage RF coil into two branches with the deployment of a unique capacitance in each branch of a leg. The dominant resonance mode of each spectrum of the proposed dual resonance double band pass birdcage coil can be utilized for the NMR imaging of a specific element at a specified MRI system. The proposed dual resonance coil can be designed into high pass/high pass and high pass/low pass configurations. The proposed method is used to design two different dual resonance coils, 31P/1H and 23Na/31P, for the NMR imaging applications in small volume at 4.7T MRI systems. Simulation results provided in the paper for both configurations of these coils proves the validity of the proposed design methodology.